Cellular panel and method and apparatus for making the same

ABSTRACT

An expandable and contractible cellular panel  10  comprises a plurality of parallel, aligned, elongated tubular sections  12  secured together at the median region of their adjacent longitudinal margins to form the panel  10.  The adjacent tubular sections  12  of the panel  10  are made of a pair of substantially identical separate strips of sheet material from those forming the other adjacent tubular sections  12.  The various adjacent pairs of strips are laminated together along their confronting longitudinal margins. Each strip is made of at least two separate flexible substrate sheets  18,20  having completely different appearances, and are secured together by welding together their longitudinal margins. The corresponding substrate sheets  18,20  of all the strips have corresponding positions in the panel  10,  so that all the substrate sheets having one appearance are on one side of the panel  10  and those having a different appearance are on the other side of the panel  10,  and the welded portions  28,28′  are located in the laminated portion of the strips where they are hidden from view.

This is a Continuation of U.S. patent application Ser. No. 08/880,569filed Jun. 23, 1997 now U.S. Pat. No. 6,045,890 which is a Continuationof U.S. patent application Ser. No. 08/273,469 filed Jul. 11, 1994,abandoned.

BACKGROUND OF THE INVENTION

The present invention relates to cellular insulation panels. It has oneof its most important applications as an insulating panel for coveringwindows or other openings. These panels most commonly comprise aplurality of tubular sections adhesively secured together. The panel canbe oriented so that the tubular sections form a horizontallycontractible and expandable panel which extends vertically, such as whencovering a doorway or other similar openings. The panel more commonly isused with an orientation where the tabular sections form a verticallycollapsible and expandable panel extending horizontally, such as whencovering a window.

In window covering, the panel is mounted upon a headrail with pull cordsextending down through holes in the panel to a bottom rail secured tothe bottom of the panel. In some panel designs, each tubular section isa strip of usually thermoplastic woven or unwoven sheet material foldedinto an open-top tube. Each tube-forming strip is initially completelyseparate from the other tubular strips forming the panel and islaminated to the adjacent strips of the panel by bands of adhesive. Thefolds of each tubular section are usually sharp or set so that theyappear as lines or bands which improve the aesthetic appearance of thepanel. Such a panel is disclosed in Dutch Published Application No.6706563 published Nov. 11, 1968 to Landa. In this Dutch publication, thecells have a rectangular, hexagonal or a pointed oval shape, dependingon the width of the adhesive bands and the degree of expansion of thecells. If the adjacent tubular sections are secured together over widesecurement bands and are fully expanded, the cells have a rectangularshape, as is shown in U.S. Pat. No. 4,019,554 granted on Apr. 26, 1977to Rasmussen.

In another form of cellular panel construction, a pair of zig-zag shapedsheets of material are placed into confronting relation and securedtogether at the abutting fold points, to form diamond-shaped cells. Thispanel construction is disclosed in U.S. Pat. No. 2,201,356 granted Nov.21, 1938 to Terrell.

The rear side of all these cellular panels, which interrupt the passageof light when covering a window, preferably have a color to reflectlight. The front side of the panels, which face into the room involved,desirably have an appearance from a strictly aesthetic standpoint. Inthe panel design where each tubular section is made of a separate sheetof material folded into a tube, one half of the sheet may be printed orembossed before it is folded into a tubular shape, so that the portionof each sheet which faces the inside of the room is provided with thedesired aesthetic appearance. The other half of each sheet, which facestowards the window has color to reflect light. If the initial sheet ofmaterial is already of a desired light color to reflect light, it canremain without any added coloring. If the sheet forming each tubularstrip is made of an expensive material to give the front side of thepanel an attractive appearance, the high cost of the portion of the samesheet which is to face the window is an undesired expense.

The panel design having diamond shaped cells, described previously, madefrom a pair of separate, confronting zig-zag shaped sheets does not havethis problem as only the front sheet must be made of the more expensivematerial. However, this type of panel is less attractive to somepurchasers than the panel having pointed oval, hexagonal or rectangularcells. Also, the method required for fabricating the panel made fromzig-zag shaped sheets is less efficient and more difficult to controlthan the method used to make a panel of separate folded strips ofmaterial adhesively secured together.

The preferred cellular panel constructed and manufactured in accordancewith the present invention overcomes these disadvantages. The panel canhave cells of any desired shape, and can be made by a very efficientstacking process. In addition, only the front side of the panel requiresa more expensive material, satisfying the aesthetic objectives ofpurchasers, and thus, the rear side can be made of a less expensivematerial, which is only required to reflect light, and aid in forming aninsulating panel.

Many of the present features of the invention are applicable to anothertype of panel to be referred to as a light-controlling cellular panel,which is used to cover primarily windows. In this panel, the frontvertical side of each horizontally extending cell is made of a sheermaterial, preferably of one mesh size, and the rear vertical side ofeach cell is made of a sheer material preferably of a different meshsize or mesh shape, to avoid a Moire effect. When the panel is in itslight-passing state, the upper or lower horizontal wall of each cell isa horizontal opaque wall which, most desirably, is wider than the heightof the cell. When one of the vertical sides of the panel is shiftedupward or downward with respect to the other vertical side of the panel,the opaque walls are pivoted into substantially vertical positions wherethey completely overlap, to obstruct the passage of light through thepanel.

Most of the methods previously used to fabricate this type oflight-controlling panel did not permit the ready manufacture of anydesired width of the panel. The commercial forms of this panel have beenusually constructed from two horizontally spaced confronting unfoldedvertical sheets of sheer material, which respectively formed thecomplete front and rear sides of the panel. Opaque strips of materialare adhesively secured at spaced vertical points between the front andrear sheer sheets of the panel. The cells of this panel have arectangular shape. As will later be described, the present inventionprovides a very efficient and effective means for manufacturing a panelhaving a similar appearance to this panel, but is constructed muchdifferently. The present invention is made from a multiplicity ofseparate identical strips of material of any desired length, cut from acontinuous web and laminated by an efficient strip stacking processwhere the panel can have any desired length. The panel can then be madeinto any width using a highly efficient stacking process.

SUMMARY OF THE INVENTION

It is preferred in all forms of the invention that the cellular panel bemade by a method and with apparatus that initially is either acontinuous tubular or flat web formed from two or more narrow,continuous substrate sheets or webs of completely different materialwhich form the front and the rear walls of the cellular panel to be madetherefrom. The continuous substrate sheets, when made of a thermoplasticmaterial, are secured together, preferably by sonically welding theirabutting longitudinal margins. This permits efficient mass production ofpanels of various constructions by cutting strips from the web andlaminating the strips together in the various ways to be described.

One form of the invention forms a panel which is not light-controlling.The panels are made at a high-speed, on one or more production lines byfeeding a pair of basic webs, or substrate sheets, in superimposedrelation past one or more sonic welders. Where one sonic welder is usedto make such a panel, the two continuous substrate sheets are weldedtogether only along one of their longitudinal margins. The resultingtwo-substrate web is first unfolded to form a flat web. The flat web isfed, immediately and sequentially to folding, adhesive-applying, webcutting and stacking apparatus, or to a different production line whenwound on a take-up reel and later unwound therefrom. The open tubularsegments of the web formed by the folding apparatus produce adhesiveconnected tubular sections of the completed panel.

To avoid unfolding and folding the web, the web is formed by a pair ofsonic welders which weld both aligned longitudinal margins of thesuperimposed continuous substrate sheets, so that the two-substrate webformed thereby forms a flat, closed tubular web; the welds are at theouter edges of the web. The flat, closed tubular web is fed to a webreforming apparatus. This apparatus first opens and then reflattens theweb, so that the welds are transitioned to the flat top and bottom facesof the web. This reformed web is then subsequently fed to theadhesive-applying, web-cutting and stacking apparatus.

This web-reforming apparatus reflattens the tubular web in a planepreferably less than 90° from the original plane of the flat tubularweb. This brings the welded margins of the flat tubular web from theouter edges of the flat web to laterally offset positions on the flattop and bottom faces of the web. As longitudinally-spaced segments ofthis flattened web become the separate tubular sections of the completedpanel, the welded portions of these tubular sections are located alongthe confronting faces thereof, which are not visible at the front orrear side of the completed panel. The two different appearing substratesheets are then only visible respectively on the opposite sides of thepanel. While in accordance with a broad aspect of the invention, thewelded portions need not be laterally offset, it is desirable becausethe offset reduces the thickness of the panel when it is raised into acollapsed condition at the top of a window. In all applications of thepresent invention where the substrate sheets are sonically welded alongtheir superimposed abutting margins, it is desirable to flatten thewelded portions of the substrate sheets. This process assures only aslight bulging of the substrate material therein, further reducing thethickness of the panel when in its collapsed configuration.

The welding and flattening of the substrate sheets is preferablyachieved by a sonically welding method similar in some respects to thatdisclosed in U.S. Pat. No. 4,177,100 granted on Dec. 4, 1979 toPennington. This patent discloses the use of heat and pressure to firstsecure together the folded trailing edge of a stationary thermoplasticsheet to the superimposed folded leading edge of a following stationarysheet. The welded superimposed stationary sheets are then unfolded andflattened by application of heat and pressure, while the sheets arestretched to pull the welded sheets apart. In the present invention, itis not necessary to pull the welded sheets apart during the applicationof the heat and pressure. In the practice of a preferred form of thepresent invention, the heat and pressure used to flatten the welds areapplied by using sonic welding apparatus designed to perform only aweld-flattening operation.

In these two methods of making cellular panels, the individual tubularsections which form the completed panel can be formed from stripstraversely cut from an adhesive coated web either before or after theyare stacked. The latter stacking method is disclosed in U.S. Pat. No.4,450,027 to Colson where, initially, an adhesive coated open tubularweb, which is not a sonically-welded tubular web of different substratesheets as just described, is spirally wound on a flat, rotating stacker.The stacker forms a flattened spiral winding of the web material, wherethe layers are adhesively secured together. The ends of this flat spiralwinding are then severed from the rest of the stack of severed layers ofmaterial to separate and divide the severed web into separate,adhesively-secured together tubular sections forming a continuouscellular panel. However, it is preferred that the adhesively-coated,multi-substrate web be first cut into strips and then stacked in amanner like that disclosed in U.S. Pat. No. 3,713,914 to Clark et al.

When forming a light-controlling panel, the initial continuous web isconstructed preferably of three, differently-appearing substrate sheetswelded together at their confronting longitudinal margins. The centralsubstrate sheet is made from an opaque material. The other two substratesheets positioned on opposite sides of the opaque central substratesheet, are made from a narrower sheet of sheer material preferably ofdifferent mesh size or mesh shape, to eliminate a Moire effect. Thethree-substrate web is preferably made by positioning one of thenarrower sheer substrate sheets over and along one of the side marginsof the wider opaque substrate sheet and positioning the other narrowersheer substrate sheet beneath the wider opaque web along the oppositeside margin thereof. These substrate sheets so positioned are moved pasta pair of sonic welders positioned along the opposite longitudinalmargins of the substrate sheets, where each welder welds only the twolayers of sheet material located thereat. The resulting three-substrateweb is then unfolded so that the completed panel can be made by one oftwo methods.

In both of these methods, the three-substrate web is initially cut intostrips of equal length. In another method, before the web is so cut, itis folded into an open tubular web by folding the opposite longitudinalmargins of the outer sheer substrate sheets of the web over the centralopaque substrate sheet of the web. A pair of adhesive bands are thenapplied to the top surfaces of the folded-over portions of the tubularweb so that the tubular strips cut from the web are adhered togetherwhen stacked over a width equal to the width of the opaque substratesheets thereof. The stacked, adhered strips are cut to size to form acontinuous cellular panel of desired length.

When the panel is oriented so that the tubular sections or cells of thepanel extend horizontally and are in vertically-spaced relation, thefront wall of each cell is formed by a front vertical sheer substratesheet of one of the tubular strips, the rear wall of each cell is formedby a rear vertical sheer substrate sheet of the same tubular strip, thebottom wall of each cell is formed by a horizontal center opaquesubstrate sheet of the same tubular strip and the top horizontal wall ofeach cell includes the folded end portions of the same tubular strip andthe opaque substrate sheet of the strip above it.

When the substrate sheets which form the front or rear sides of thepanel are shifted up or down with respect to each other, the initiallyhorizontal opaque substrate sheets of the various laminated strips areshifted from a horizontal position where light passes through the panelto an inclined vertical position where the opaque substrate sheets ofadjacent strips overlap, to stop the passage of light through the panel.

Another method for Fabricating a light-controlling cellular paneleliminates the folding of the initially flat three-substrate webs.Before the flat web is cut into strips, spaced bands of adhesive areapplied to the top surface of the web in a pattern which effects aspecial strip laminating pattern. The adhesive-coated flat web is thentransversely cut into flat strips of equal length. The strips arelaminated together by sequentially laterally shifting the strips fromtheir original aligned longitudinally spaced positions. Each laterallyshifted strip is next laminated so that the outer longitudinal margin ofone of the outermost light-passing substrate sheets of each strip isadhered to the strip cut before it at the innermost longitudinal marginof the corresponding light-passing substrate sheet thereof, and theinner longitudinal margin of the other outermost light-passing substratesheet of the former strip is adhered to the latter previously cut stripat the outer longitudinal margin of the corresponding outer substratesheet. The resulting panel formed from the laterally-shifted laminatedstrips, when expanded, places the light-passing substrate sheets inpositions where one of the light-passing substrate sheets of each stripforms a vertical front wall of an expanded tubular section of the panel,the other light-passing substrate sheet of the same strip forms avertical rear wall of the adjacent expanded tubular section of thepanel, and the opaque substrate sheet of that strip forms the horizontaltop or bottom wall in common between adjacent cells of the panel.

When the light-passing substrate sheets on one side of the panel areshifted vertically relative to the light-passing substrate sheets on theopposite side thereof, the opaque central substrate sheet of eachlaminated strip of the panel is pivoted from its initial horizontalposition where light can pass through the panel to a position where theopaque substrate sheets of adjacent cells of the panel overlap oneanother to obstruct the passage of light through the panel.

Other advantages and features of the invention will become apparent uponmaking reference to the specification, claims, and drawings to follow.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of two adjacent tubular sections of thepreferred panel of the present invention which is adapted forapplications where the panel covers a window in its normal use and israisable to the top of a window when not in use;

FIG. 1A is a fragmentary, enlarged vertical sectional view through thelaminated portions of two adjacent tubular sections of the panel andshows spaced adhesive bands which secure together the adjacent wallsections of these tubular sections of the panel;

FIG. 2 is a larger perspective view of one of the tubular sections shownin FIG. 1, specifically showing the adhesive bands on the top of eachtubular section;

FIGS. 3A-3F respectively show the different operations performed on aproduction line upon a pair of superimposed continuous substrate sheetsof different material to form a multi-substrate sheet web which is woundupon a reel and then subsequently unwound and applied to the secondsection of a production line, shown in block form in FIG. 5, where theweb is coated with adhesive and cut into strips which are then laminatedto form a continuous cellular panel;

FIGS. 4 and 4′ taken together show an exemplary production line forperforming the various steps illustrated in FIGS. 3A-3F;

FIGS. 4A and 4B disclose slit/weld sensor pins which detect whether theslit/weld anvils are operating properly;

FIGS. 4C-4H disclose various views of the web reforming stations of theapparatus of FIG. 4′, where an initially formed flattened tubular web isreformed into a tubular web flattened in a different plane;

FIG. 4I is a transverse vertical sectional view along section line 4I—4Iin FIG. 4′ through an ultrasonic horn assembly which sets a sharp foldin the side edges of the preformed web;

FIG. 4J is a perspective view showing in more detail a portion of thestress-relieving station of the production line of FIG. 4′, whichincludes a heated cambered plate over which the re-formed web is fed;

FIG. 4K is a longitudinal vertical sectional view along section line4K—4K in FIG. 4J through a pair of drive and nip rollers at one end ofthe cambered plate;

FIG. 4L is a transverse vertical sectional view along section line 4L—4Lin FIG. 4K through the nip roller assembly;

FIGS. 4M and 4N show a modification of the production line of FIG. 4,where a number of multi-substrate webs are simultaneously formed on anumber of production lines formed of common elements as in FIGS. 4 and4′;

FIG. 4O shows the different elements of a sonic horn used throughout theproduction lines to be described hereafter;

FIG. 5 is a block diagram showing how a multi-substrate web formed bythe production line of FIGS. 4 and 4′ is further processed by applyingadhesive to the web, cutting the web into strips, and then stacking thestrips to form a completed continuous cellular panel;

FIG. 6 is a perspective view of two adjacent tubular sections of a panelwhere each tubular section is an open top tube for a panel which coversa window in its normal use and is raisable to the top of a window whennot in use;

FIG. 6A is a fragmentary enlarged vertical sectional view through thelaminated portions of two adjacent tubular sections of the panel of FIG.6 and shows spaced adhesive bands which secure together the adjacentwall sections of the tubular sections of the panel;

FIG. 7 is a larger perspective view of one of the tubular sections shownin FIG. 6, specifically showing the adhesive bands on the top of eachtubular section;

FIGS. 8A-8F respectively show the different operations performed on aproduction line upon a pair of superimposed continuous substrate sheetsof different material to form a multi-substrate sheet web which is woundupon a reel and then subsequently unwound and applied to the secondsection of a production line where the web is folded, coated withadhesive and cut into strips which are then laminated to form thecontinuous cellular panel shown in FIG. 6;

FIG. 9 shows part of a production line for performing the various stepswhich form the multi-substrate sheet web of FIGS. 8A-8F;

FIG. 10 is a block diagram showing how the multi-substrate web formed bythe production line of FIG. 9 is further processed by folding themulti-substrate web, applying adhesive to the web, cutting the web intostrips and then stacking the strips to form a completed continuouscellular panel of FIG. 6;

FIG. 11 is a perspective view of three adjacent cells of yet anotherembodiment of the present invention which is a light-controllingcellular panel and is adapted to applications where the front and rearsides of the panel are movable vertically relative to one another fromthe light-passing position of FIG. 11 to one (not shown) where lightpassage through the panel is blocked;

FIGS. 11A-11B more clearly show the spaced bands of adhesive whichsecure together the adjacent cells or tubular sections of FIG. 11;

FIGS. 12A-12D respectively show the different operations performed on aproduction line upon three superimposed continuous substrate sheets ofdifferent material to form a multi-substrate sheet web which is to forma light-controlling cellular web which is wound upon a reel and thensubsequently unwound and applied to the second section of a productionline shown in block form in FIG. 14, where the web is folded, coatedwith adhesive, and cut into strips which are then laminated to form thecontinuous cellular panel of FIGS. 11 and 12;

FIG. 13 shows part of a production line for performing the various stepswhich form the multi-substrate sheet web of FIGS. 12A-12D;

FIG. 14 is a block diagram showing how the multi-substrate web formed bythe production line of FIG. 13 is further processed by folding themulti-substrate sheet web, applying adhesive to the web, cutting the webinto strips and then stacking the strips to form the completedcontinuous cellular panel of FIG. 11;

FIGS. 14A-14D illustrate the tubular web produced by the production lineof FIG. 13 respectively, before the web is folded, after it is folded,after adhesive is applied to it, and after strips cut from it arelaminated together;

FIG. 15 is a perspective view of a plurality of cells of anotherlight-controlling panel embodiment of the present invention;

FIGS. 15A-15B are fragmentary enlarged views of the panel of FIG. 15showing the adhesive bands connecting adjacent multi-substrate stripswhich form the cells of the panel;

FIG. 16 is the multi-substrate web produced by the production line inFIG. 13 coated with bands of adhesive;

FIG. 17 shows a plurality of strips cut from the web of FIG. 16 andlaterally shifted with respect to each other, with arrows indicating thepoints where the adhesive band coated on the strip will adhere thelaterally shifted strips together, to form the light-controllingcellular panel of FIG. 15;

FIG. 18 is a block diagram showing how the multi-substrate web formed bythe production line of FIG. 13 is further processed to form thelight-controlling cellular panel of FIG. 15; and,

FIG. 19 shows the strip delivery and lateral strip-shifting conveyormeans used to laminate the multi-substrate strips together to form thelight-controlling cellular panel of FIG. 15.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The Embodiment of FIGS. 1-5

While this invention is susceptible of many different forms, there isshown in the drawings and will herein be described in detail variouspreferred embodiments of the invention, with the understanding that thepresent disclosure is to be considered as an exemplification of thebroad principles of the invention and is not intended to limit the broadaspects of the invention to the embodiments illustrated. The variousdifferent details of the various embodiments of the invention are, insome cases, due to their different applications and, in other cases, dueto progressive improvements to earlier developed embodiments.

Referring now to the drawings, FIG. 1 shows a portion of a non-lightcontrolling closed tube cellular panel 10 in its expanded state, formedfrom laminated horizontally elongated vertically aligned tubularsections or cells 12. This is the most preferred panel embodiment of thepresent invention where the panel is not light-controlling as are otherpanels to be described. FIG. 2 shows a single cell or tubular section 12of the cellular panel 10. The cell 12 has a front wall portion 14 madefrom a first continuous thermoplastic substrate sheet 18, having adesired aesthetic appearance, and a rear wall portion 16 made from asecond continuous thermoplastic substrate sheet 20 of about the samethickness, length and width as the first sheet 18. The second sheet 20is made of different appearing, preferably much less expensive,light-reflecting material from the substrate sheet 18. The cell 12 alsohas a top wall portion 15 and a bottom wall portion 17. Each tubularsection 12 is laminated to the next adjacent tubular section 12 byspaced bands 11-11′ of adhesive which are spaced apart to provide anadhesive-free band 15 a centered on the top wall portion 15 of each cell12 to receive a drill for drilling pull cord-receiving holes (notshown). Folds 13-13′, shown in FIG. 1A, are formed in the centers of thesheets 18 and 20, so that when the tubular sections 12 are expanded bythe weight of a bottom rail (not shown) and the weight of the panelitself above the rail, the cells have a hexagonal shape.

The cell 12 is initially formed by first superimposing the two separatecontinuous substrate sheets 13,20 as shown in FIG. 3A. The superimposedsubstrate sheets 18 and 20 have superimposed longitudinal marginalportions adjacent their longitudinal edges 22,22 and 22′,22′ which aresecured together, most preferably by sonic welding. As shown in FIG. 3B,circular pointed slit/weld anvils 24,24′ are positioned slightly inwardof the aligned pairs of longitudinal edges 22,22′ of the two substratesheets 18,20. The anvils 24,24′ may be driven by a pulley system (notshown) or other drive means or can be stationary. Driven rotary anvilsare preferred to lessen the wear on the anvils. The periphery of eachanvil 24,24′ is tapered on each side 24 b,24 b′ toward the pointed edge24 a,24 a′ thereof. A common ultrasonic horn 26 having a flat end face26 a is positioned under the second substrate sheet 20 and extends atleast the entire width of the two substrate sheets 18,20. As the twosubstrate sheets 18,20 pass between the slit/weld anvils 24,24′ and thecommon ultrasonic horn 26, the longitudinal marginal portions of thesheets inwardly of the pointed edges 24 a,24 a′ of the anvils 24,24′ arewelded together by the ultrasonic horn 26 vibrating the two substratesheets 18,20 against the slit/weld anvils 24,24′. Narrow continuouslongitudinal welded portions 28,28′ are formed at the inside faces 24b,24 b of the slit/weld anvils 24,24′. The welded portions 28,28′ have awidth of about the thickness of each of the substrate sheets 18,20. FIG.3C is an enlarged view of a weld formed by the process shown in FIG. 3Band shows the pointed edge 24 a′ of the anvil 24′, the superimposedsubstrate sheets 18,20, and a portion of the ultrasonic horn 26positioned therebelow.

In addition to sonically welding the superimposed substrate sheets 18,20together, the slit/weld anvils 24,24′ also slit through the superimposedsubstrate sheets 13,20 at the location of the anvil pointed edges 24a,24 a′. This produces selvedge portions 32,32′ of the superimposedsubstrate sheets 18,20 adjacent the pointed edge 24 a,24 a′ of eachslit/weld anvil 24,24′ which are collected in a process to be describedin more detail.

The welding process described forms a continuous, flat, multi-substratetubular web 30 (FIG. 3B) in a horizontal plane, with the differentappearing substrate sheets 18,20 constituting the opposite flat sidesthereof. The panel 10 is formed from longitudinally spaced segments cutfrom this web 30 and laminated preferably in a manner to be described.The web 30 shown is reformed so that a flat tubular web 30′ (FIG. 3F) isformed having the welded portions 28,28′ thereof on the top and bottomof the opposite flat sides of the reformed flattened web 30′. To thisend, the tubular web 30 is first guided from a horizontal plane to avertical plane (FIG. 3D). The flat tubular web 30 is next opened andthen flattened in a plane approaching a right angle to the originalplane of the flat web 30 to bring the welded portions 28-28′ to the flattop and bottom faces of the reformed tubular web 30′, but laterallyspaced in opposite directions from the center line of the web so thewelded portions 28-28′ webs are not in alignment, as shown in FIG. 3E.As there shown, the reformation of the web 30 causes the welded portions28-28′ to project above and below the top and bottom faces of thereformed web 30′. It is desirable that the reformed tubular web 30′ havea similar thickness throughout; therefore, the projecting weldedportions 28-28′ of the tubular web 30′ are flattened to produce atubular web 30 with similar thickness throughout as shown in FIG. 3F.

FIG. 3E illustrates this weld flattening process which utilizes a weldflattening ultrasonic horn 33, similar to the welding ultrasonic horn 26shown in FIG. 3B, but positioned above the reformed tubular web 30′, anda preferably driven cylindrical rotating anvil 34 positioned below thereformed tubular web 30′. As the tubular web 30′ masses between the webflattening ultrasonic horn 33 and the cylindrical rotating anvil 34, thewelded portions 28,28′ of the tubular web 30′ are flattened by thepressure applied by the flattening ultrasonic horn 33 vibrating thetubular web 30′ over the cylindrical rotating anvil 34. The opposite topand bottom layers of the tubular web 30′ are not welded together becausethe conditions of the process are controlled to avoid a weldingoperation. Exemplary weld flattening conditions are disclosed in theprocess specification to follow.

FIG. 3F shows the reformed tubular web 30′ with the welded portions28,28′ out of alignment and substantially flattened. As shown, slightbulges 36,36′ remain in the tubular web 30′ at the welded portions28-28′.

FIGS. 4 and 4′ show a full production line for manufacturing the closedreformed tubular web 30′ made of two continuous substrate sheets 18,20of differently appearing material. FIG. 4′ is a continuation of the lineshown in FIG. 4. Narrow webs of the two continuous substrate sheets18,20 wound on driven supply reels 40,42 are unwound by the pullingforce of drive and nip rollers 35,37. The substrate sheets 18,20 passthrough a series of rollers designed to maintain tension in thesubstrate sheets 18,20. To this end, the substrate sheets 18,20 firstrespectively pass over idler rollers 44, and down under conventionaldancer tensioning rollers 46 which are mounted on arms (not shown) whichmove up and down to keep a constant tension in the continuous substratesheets 18,20. The tendency of these and other dancing rollers, to bedescribed, to move up and down is opposed by a feedback control systemwhich controls the driving speed of the supply reels 40,42 and take-upreel 128 upon which the completed web 30 is wound. The substrate sheets18,20 continue over second idler rollers 48. After the substrate sheets18,20 pass over idler rollers 48, the first substrate sheet 18 passesthrough a conventional photo-cell controlled edge guidance rollerassembly 50 which keeps the sheet in longitudinal alignment. Thesubstrate sheet 18 next passes under a third idler roller 52 and to apair of idler rollers 60-62. The roller assembly 50 includes a supportframe 50′ mounted for pivotal movement about a vertical axis andphoto-cells 50″ sensing the positions of the edges of the substratesheet 18. After passing over the second idler roller 48, the secondsubstrate sheet 20 passes under the third idler roller 52 and through aconventional photo-cell controlled edge guidance roller assembly 50,like the assembly 50 just described. The substrate sheet 20 then passesup to the pair of idler rollers 60,62. At the idler rollers 60,62, thesuperimposed substrate sheets 18,20 have their longitudinal margins oredges aligned.

The two superimposed substrate sheets 18,20 next pass through adjustablelongitudinally-spaced non-rotating shafts 54,56,58, which are verticallyadjustable. The shafts 54,56 adjust the elevation of the twosuperimposed substrate sheets 18,20. The shaft 58 is positioned belowshafts 54,56 and is vertically adjustable to control tension in thesubstrate sheets 18,20 to eliminate any wrinkles at the weldingassembly. The first substrate sheet 18 passes over the shaft 54 andbetween the shafts 56 and 58. The second substrate sheet passes underthe shaft 54 and between the two shafts 56 and 58.

The superimposed substrate sheets 18,20 next pass between the commonultrasonic horn 26 and the rotating or stationery slit/weld anvils24,24′, where the sheets' opposite longitudinal edges 22,22′ are weldedtogether, as previously described with respect to FIGS. 3B-3C. This, asnoted before, forms a continuous tubular web 30 of differently appearingsubstrate sheets 18,20 superimposed and welded together in thehorizontal plane. The welding process carried out by the ultrasonic horn26 and rotating slit/weld anvils 24,24′ produce selvedge portions 32,32′at the longitudinal edges 22,22′ of the tubular web 30. The tubular web30 and selvedge portions 32,32′ then pass through a pair of slit sensorpins 59,59.

The pair of slit sensor pins 59,59 are further shown in FIGS. 4A and 4Band extend upward from a common controlled shaft 59′. The sensor pins59,59 pass between the selvedge portions 32,32′ and the welded portions28,28′ of the substrate sheet 18,20 before the same reaches the rollers35,37. The sensor pins 59,59 detect whether the slit/weld anvils 24,24′have completely slit through the substrate sheets 18,20 which wouldnormally indicate that the slit/weld anvils 24,24′ are operatingproperly. The slit/weld anvils will wear over time and eventually failto completely slit through the substrate sheets 18,20. If this occurs,the portion of the substrate sheets 18,20 not slit engages the slitsensor pins 59,59, which will rotate the common controlled shaft 59′forward. As shown in FIG. 4B, this forward rotation of the shaft 59′ isconnected to a switch means 61 which shuts down the production line sothat the worn, defective slit-weld anvil can replaced.

The tubular web 30 and selvedge portions 32,32′ next pass between adriven bottom roller 35 and a top nip roller 37, which pull thesubstrate sheets 18,20 through the welding assembly. The selvedgeportions are wound on take-up reel 64. The tubular web 30 then passesover an idler roller 63 which restores the elevation of the tubular web30 to the elevation occupied by the tubular web 30 at the weldingapparatus.

After the welding, but before the weld flattening operation, aspreviously described, web-reforming means are provided which transitionthe welded portions 28,28′ of the tubular web 30 from the outer edges ofthe tubular web 30 to positions on top and bottom of a flat reformedtubular web 30′, as shown in FIG. 3E. This transition of the weldedportions 28,28′ preferably takes place in the specific mannerillustrated in FIGS. 4C-4H.

The tubular web 30 lies in a horizontal plane after exiting theultrasonic horn 26 and slit/weld anvil 24,24′ assembly and is twistedinto a vertical plane by passing through one of the vertical slots 67formed between a first pair of spaced vertical rods 68,68 of a firstcomb-like structure 66 shown in FIGS. 4′ and 4C. The vertical,horizontally spaced rods 68 are mounted on a base 66 supported on a post67. The tubular web 30 then passes through a second comb-like structure66′ identical to the first comb-like structure 66. Using two comb-likestructures assures the tubular web 30 is kept in a vertical plane beforeit enters the next steps of the process; it also reduces stress on theweb 30.

The vertically oriented tubular web 30 is then expanded to receive aninsert structure 70 illustrated in greater detail in FIGS. 4D-4G. Asseen in FIG. 4D, the insert structure 70 floats within and keeps thetubular web 30 open, with the welds 28,28′ at the top and bottom of theweb 30. The tubular web 30 is then re-flattened in a plane slightly lessthan 90 degrees from the plane of the interfaces between the substratesheets 18,20 when they were originally welded together. FIG. 4E showsthe insert structure 70 including a pair of horizontally spaced verticalsupport plates 72,72′ between which are rotatably mounted two narrow,vertically spaced rollers 74,76 having outwardly tapering peripheralportions 74 a,76 a ending at peripheral flat crown portions 74 b,76 b. Ahorizontal, rearwardly tapering guidance plate 78 is secured to thevertical support plates 72,72′ and extends forwardly therefrom. Thetapered guidance plate 78 rests on a stationary shaft 86 for support.FIG. 4F illustrates in dashed lines a cross-section of the tubular web30 passing around the insert structure 70, with the flat crown portions74 b,76 b of the roller peripheries engaging and expanding the open web,so that the welded portions 28,28′ at the top and bottom of thevertically oriented tubular web 30 ride along the flat crown portions 74b,76 b.

To prevent the guidance plate 78 from shifting in a lateral direction, apair of rotatable plate-holding members 78′ are positioned on oppositesides of the guidance plate 78. The members 78′ rotate while pressingagainst the cuter sides of the web against the edge of the guidanceplate 78 as shown in FIGS. 4′ and 4F.

The expanded web 30 is then kept expanded in a horizontal plane by theguidance plate 78 and in a vertical plane by the flat crown portions 74b,76 b of rollers 74,76. A pair of fixed cylindrical outer guide members77,79 are provided with tapered slotted portions 81 a,83 a which closelybut in spaced relation confront the forwardly facing sides of therollers 74,76 respectively at the upper and lower margins thereof. Theouter guide members 77,79 are formed by a pair of bearings 77 a-b, 79a-b with tapered confronting surfaces 77 a′-b′ and 79 a′-b′ which arespaced apart by O-rings 81,83 and define grooves 81 a,83 a with thetapered surfaces 77 a′-b, 79 a′-b′ closely confronting the flat crownportions 74 a′-b, 76 a-b of the rollers 74,76 of the insert structure70. The forward movement of the expanded web 30 pushes the insertstructure 70 forward towards the outer guide members 77,79 so that theexpanded web 30 is forced between the outer guide members 77,79 and thevertically spaced rollers 74,76. FIG. 4G is a view of the top portion ofFIG. 4E. It shows the welded portion 28 riding along the flat crownportion 76 b as the web 30 passes between the roller 76 and outer guidemember 77.

As seen in FIGS. 4′ and 4H, after tubular web 30 passes around theinsert structure 70, the web 30 passes between a stationary groovedsleeve 86′ and a stationery grooved sleeve 87′. The insert structureguide plate 78 rests on the stationary shaft 86. The sleeves 86′,87′ aresecured by one or more set screws 86″,87″ to stationary shafts 86,87.The shaft 87 is vertically adjustable and is located slightly downstreamand above the shaft 86. As best seen in FIG. 4H, the sleeves 86′,87′have laterally offset grooves 88,89 into which the bulging weldedportions 28,28′ of the web 30 enter respectively, to laterally offsetthe welded portions 28,28′. This lateral offset reduces the thickness ofthe completed cellular panel 10 when in a collapsed configurationbecause the welded portions 28,28′ slightly bulge the tubular web 30.The grooved sleeves 86′,87′ are positioned by set screws 86″ and 87″ toobtain the desired offset positions. The stationary shafts 86,87 maycarry additional grooved sleeves if manufacturing a plurality of webs atthe same time, as seen in FIGS. 4M and 4N.

The web 30, after leaving the grooved sleeves 86′,87′, enters the weldflattening assembly comprising the flattening ultrasonic horn 33 andcylindrical rotating anvil 34 shown in FIG. 3E. The top and bottom welds28,28′ are located to the right and left of center lines of the top andbottom walls of the reformed web 30′, as shown in FIG. 3E. The reformedtubular web 30′ passes between the flattening ultrasonic horn 33 andcylindrical rotating anvil 34 shown in FIG. 3E which flattens theprojecting weld 28,28′ of the reformed tubular web 30′ to produce a webof similar thickness throughout.

As shown in FIGS. 4′ and 4I, the reformed web 30′ passes between anotherultrasonic horn 92 and a cylindrical rotating anvil 94 similar to theweld flattening assembly previously described. This second ultrasonichorn 92 vibrates the reformed web 30′ against the second cylindricalrotating anvil 94 to set the folds made at the outer longitudinal edgesof the reformed web 30′. As best seen in FIG. 4I, the second cylindricalrotating anvil 94 has a recessed portion 96 substantially at its centerwhere the welded portions 28,28′ pass through. Without the recessedportion 96, the bulging welded portions of the web 30′ would becomeheated to a much higher temperature than the rest of the web, whichcould cause a possible undesired welding together of the overlyinglayers of the web. This prevents the second ultrasonic horn from workingdirectly onto the welded portions 28-28′ and concentrates the workperformed on the longitudinal edges of the reformed web 30′.

After this foldsetting, the reformed web 30′ passes between drive roller110 and nip roller 112 (FIG. 4′). The nip roller 112 is a biascontrolled roller. The nip roller 112 is, thus, adjustable allowing thenip roller 112 to apply more pressure to one side of the reformed web30′ than the web's other side. Such a roller improves the control overthe path of the web. The thicknesses of the substrate sheets 18,20forming the web 30′ can be different. Due to this possible variation inthickness, the web may try to move laterally as it passes between thedrive and the nip rollers 110,112. The bias control nip roller 112prevents any lateral movement of the web 30′ and assures the web 30′travels in a straight path.

FIGS. 4K and 4L illustrate the bias control nip roller 112 in moredetail. FIG. 4K is a side view of the nip roller 112 taken along theline 4K—4K in FIG. 4J. FIG. 4L is a cross-sectional view taken along theline 4L—4L in FIG. 4K. The nip roller 112 has a grooved sleeve 130 whichrides about a plurality of bearings 131 adjacent a common shaft 132. Thegrooved sleeve has outer sections 133,134 which contact the reformed web30′. The grooved sleeve 130 allows the welded portions 28,28′ to passwithout contacting the nip roller 112. Spring assemblies 135,136,located on each end of the shaft 132, apply pressure independently toeach outer section 133,134 of the nip roller 112. Set screws 137,138allow the pressure to be adjusted on each outer section 133,134 of thenip roller 112. As described before, more pressure can then be appliedto one side of the reformed web 30′ than the other to prevent anylateral movement of the web 30′ due to the different thicknesses of thesubstrate sheets 18,20.

The web 30′ is next pulled under tension over a heated upwardly honed orcambered plate 106, as shown in FIG. 4′ and FIG. 4J, to relieve thestresses produced in the flattened welded portions 28,28′ of thereformed tubular web 30′. The cambered plate 106 is heated by a heatingelement 108 positioned below the plate. The tubular web 30′ is forceddownward against the heated cambered plate 106 by the passage or the web30′ between drive and nip rollers 110,112, the nip roller 112 beingpositioned below the lower inlet end of plate 106 and then between driveand nip rollers 116,114 at the outlet end of the plate 106 as seen inFIG. 4′ and FIG. 4J.

Nip roller 114 is also a bias control roller, identical to nip roller112, to assure the web passes over the upwardly honed cambered plate 116in a straight path.

Heating the reformed tubular web 30′ under tension relieves stressesproduced in the welded portions 28,28′ of the tubular web by the weldingprocess. These stresses are apparent by a longitudinal bow in thereformed tubular web 30′ and ripples at the welds 28,28′ prior topassing over the heated cambered plate 106. The relief of these stressesin the welds 28,28′ minimizes any ripples and produces a flat, unbowedtubular web 30′.

As seen in FIG. 4′, the reformed tubular web 30′ passes under a furtheridler roller 118, over an adjacent idler roller 120 and passes under adancer tensioning roller 122 which controls tension in the web 30′. Theweb 30′ proceeds over the two idler rollers 124,126 to an individualpowered take-up reel 128 for later fabrication, as shown in FIG. 4, oris immediately processed to form the cellular panel 10.

Although FIGS. 4A-4L show the manufacture of only one tubular web 30 ata time, the comb-like structure 66 (FIG. 4N) has a plurality of verticalrods 68 to receive a number of tubular webs 30 a- 30 d simultaneously.Such a modified production line is shown in FIG. 4M. As seen in FIG. 4M,a number of tubular webs 30 a- 30 d can be manufactured from a wider,continuous tubular web of a pair of supplemental continuous substratesheets 18 a,20 a. The continuous substrate sheets 18 a,20 a, made ofsimilar material as substrate sheets 18,20, are unwound from poweredsupply reels (not shown) and pass through a similar set of rollers (likerollers 44 through 60), as shown in FIG. 4. These rollers are wider,however, to accommodate the wider substrate sheets 18 a,20 a. Thesuperimposed wider substrate sheets 18 a,20 a then are passed between acommon ultrasonic horn 26′ vibrating the wider superimposed substratesheets 18 a,20 a against a plurality of laterally spaced rotatingslit/weld anvils 24′ positioned adjacent to one another. This produces aplurality of closed welded tubular webs 30 a- 30 d which pass through aplurality of slit sensor pins 59 (as described before). The webs 30 a-30 d pass between the vertical rods 68 in the comb-like structures66,66′ (FIG. 4N). Each tubular web 30 a- 30 d is then further processedin the manner just described and wound onto separate reels.

Exemplary specifications for some of the production lines describedinclude a sonic horn like that shown in FIG. 4O. The sonic horn isconnected to a booster B1 driven by a converter C1 which is fed from acommercial AC power line.

The following are a set of exemplary specifications for the productionline shown in FIGS. 4 and 4′:

1. Web feed speed: 17.5 feet per minute

2. Specification of substrate sheet 18: 0.007″ thick woven polyesterfabric.

3. Specification of substrate sheet 20: 0.007″ thick non-woven polyesterfabric.

4. Specification of sonic welder ultrasonic horn 26:

a. power supply; converts 50/60 Hz line current to 20 KHz electricalenergy;

b. converter; converts electrical oscillations into mechanicalvibrations.

c. booster (1:2 ratio); modifies the amplitude of vibrations.

d. amplitude (65% setting at power supply control); function of hornshape, peak to peak displacement of the horn at its work face.

e. horn; ½″×9″ carbide tipped face titanium.

f. manufactured by Branson Ultrasonics corporation, 41 Eagle Road,Danbury, Conn. 06813 identified by Model Number 900B.

5. Specification of slit/weld anvil 24: stationary, 1″ diameter, ⅛″wide, 150 degrees, 0.005 r.

6. Slit/weld anvil 24 pressure against web: 40 PSI.

7. Specification of weld-flattening ultrasonic horn 33:

a. power supply; converts 50/60 Hz line current to 20 KHz electricalenergy;

b. converter: converts electrical oscillations into mechanicalvibrations.

c. booster (1:1.5 ratio); modifies the amplitude of vibrations.

d. amplitude (80% setting, pneumatic engagement and retraction.

e. horn; ½″×9″ carbide tipped face titanium.

f. manufactured by Branson Ultrasonics Corporation, 41 Eagle Road,Danbury, Conn. 06813 identified by Model Number 900AO.

8. Specification of weld-flattening cylindrical anvil 34: 4″ diameter,driven at 17.85 feet per minute (2% overdrive for web tensioning).

9. Specification of grooved guide rollers 77,79: ⅞″ diameter, {fraction(1/16)}″ spacing (o-ring), 1⅞″ vertical distance between upper and lowerpairs.

10. Specification of guide plate 78: 0.030″ thick, {fraction (9/16)}″ to1{fraction (5/16)}″ taper over 9½″ distance.

11. Specification of foldsetting ultrasonic horn 92:

a. power supply; converts 50/60 Hz line current to 20 KHz electricalenergy;

b. converter; converts electrical oscillations into mechanicalvibrations.

c. booster (1:1.5 ratio); modifies the amplitude of vibrations.

d. amplitude (80% setting, pneumatic engagement and retraction.

e. horn; ½″×9″ carbide tipped face titanium.

f. manufactured by Branson Ultrasonics Corporation, 41 Eagle Road,Danbury, Conn. 06813, identified by Model Number 900AO.

12. Specification of foldsetting cylindrical anvil 94: 4″ diameter,driven at 17.85 feet per minute (2% overdrive for web tensioning) withweld seam clearance relief.

13. Pneumatic pressure exerted by weld-flattening ultrasonic horn 33against weld-flattening cylindrical anvil 34: 12-14 PSI.

14. Pneumatic pressure exerted by foldsetting ultrasonic horn 92 againstfoldsetting cylindrical anvil 94: 22-24 PSI.

15. Specification of nip rollers 112,114: 1⅛″ wide, 2″ diameter, ¼″ widegroove.

16. Specification of heated cambered plate 106: 230 degrees F., ½″ riseat center 24″ length.

17. Specification of drive roller peripheral speed: 17.94 feet perminute (0.5% tensioning overdrive).

FIG. 5 is a block diagram illustrating the steps of forming a cellularpanel 10, from a continuous flat reformed tubular web like web 30′,30a,30 b,30 c or 30 d. The functions performed by the blocks shown thereinmay be performed, for example, by the tension control web aligning,adhesive applying, and web cutting and stacking chamber disclosed inU.S. Pat. No. 4,450,027 or copending Application Ser. No. 07/839,600filed Feb. 28, 1992. A pair of reels of a pair of reformed webs 30 a and30 b ′ are shown in FIG. 5 supported one above the other. The web 30 a′on one reel is unwound in a horizontal plane while it passes firstthrough tension control and web aligning means 41 comprising rollers(not shown) to maintain tension and laterally align the tubular web 30a′. The tubular web 30 a′ then passes through an adhesive applying means43 which applies the two bands 11,11′ of adhesive, (FIG. 1). The twobands of adhesive 11,11′ are applied to the portion of the web 30 a′ toform the top wall portion 15 of each cell 12 formed from the tubular web30 a,(FIG. 2). As shown in FIG. 1A, the bands of adhesive 11,11′ areapplied over the welded portions 28,28′ of the tubular web 30 a′ toreinforce the welds. The bands of adhesive 11,11′ are spaced to leavethe center portion of the top wall portion 15 of the tubular web 30 a′free of adhesive. This allows for drilling through the center of the topwall portion 15 of the tubular web 30′ to accommodate the drawstrings ofa complete cellular panel 10 without the drilling means coming intocontact with the adhesive. If adhesive was applied along the entire topwall portion 15, the drilling means would have to be periodicallycleaned or replaced after the adhesive built up on the drilling means.

Referring again to FIG. 5, the tubular web 30 a′ is then cut intoidentical tubular strips by a cutting means 45. The strips cut from theweb 30 a′ form the cells or tubular sections 12 of the panel 10. The web30 a′ is then fed by high speed conveyor means 47 to a stacking chamber49, both similar to that disclosed in U.S. application Ser. No. 839,600.The stacking chamber 49 receives the flat tubular strips through a strippass-through slot (not shown) located in the floor of the stackingchamber extending the length of the tubular strips. The conveyor means47 includes a stationary conveyor belt section 47 a which separates thecut strips and a raisable conveyor section 47 b which is raised by alifter means 51. The conveyor sections 47 a,47 b may each includesuction conveyor belts which hold the strips by suction thereon. Thelifter means 51 raises the raisable conveyor 47 b through the slot inthe floor of the stacking chamber 49. This pushes the strip, held on thebelts by suction, off the belts and up against the strip above it. Thisstrip is thus raised in the stacking chamber 49, so that the adhesivebands 11,11′ adhere to the bottom of the strip above it, as shown inFIG. 1A. The movement of the belt forming the raisable conveyor 47 b isstopped when a strip is in alignment along its length with the inletslot of the stacking chamber 49.

To properly align the tubular strips in the stacking chamber 49, thebottom of the stacking chamber may be defined by a pair of verticalconfronting walls (not shown) which are spaced apart a distance slightlygreater than the width of the strips. These walls thus laterally aligneach strip being pushed into the stacking chamber with the strip aboveit. The upper portion of the stacking chamber preferably has oppositeupwardly diverging walls so that the laminated strips raised momentarilyin the chamber will not get stuck in the chamber. The proper timing ofthe operation of all of the stations of the production line shown inFIG. 5 is determined by suitable and conventional control meansidentified by a block 53 in FIG. 5.

After a strip is pushed into the stacking chamber and adhered to thestrip above it, the lifter means 51 lowers the raisable conveyor 47 bwhich passes down through the pass-through slot in the bottom of thestacking chamber 49. The strip just stacked separates from the raisableconveyor as it is pulled against the floor of the chamber 49 by thedownward movement of the raisable conveyor 47 b. The movement of thebelt of the raisable conveyor 47 b then resumes as it receives the nextstrip to be pushed into the stacking chamber 49. The sequence ofoperation just described is repeated to form the expandable cellularpanel 10 in a mass production operation. When one of the web reels 30 a′is completely unwound, a photo cell (not shown) senses this conditionand stops the web feed. The leading edge of the other reel, for webmaterial 30 b′, is then spliced to the trailing edge of the completelyunwound web 30 a′.

Embodiment of FIGS. 6-10

FIGS. 6-10 illustrate another embodiment of the present invention wherea non-light controlling cellular panel 10′ is made similar to the panel10 shown in FIG. 1, except that it is formed from a plurality ofhorizontally elongated open top tubular sections 12′ or cells ratherthan closed tubular sections. FIG. 6 shows a portion of such a cellularpanel 10′. As seen in FIG. 7, each tubular section 12′ is formed offront and rear substrate sheets 18′,20′ of two differently appearingsubstrate materials. Each tubular section 12′ has a top wall portion15′, formed by spaced inturned longitudinal margins of the substratesheets 18′ and 20′, a bottom wall portion 17′ formed by the oppositelongitudinal margins of the substrate sheets welded together at 28 a,and front and rear wall portions 14′ and 16′ respectively formed by thesheets 18′ and 20′. Each tubular section 12′ is formed from strips cutfrom a folded continuous two-substrate web formed by folding theinitially flat web 31, (FIG. 8F). The outer longitudinal marginalportions of the unfolded continuous multi-substrate web 31 are foldedover the central portion of the web to form an open tubular flat webwhich is coated with adhesive, cut into strips, and the adhesive-coatedstrips are sequentially stacked. The flat web 31 is made in the mannershown in FIGS. 8A-F.

FIG. 8A shows two differently appearing substrate sheets 18′, 20′ withtheir opposite longitudinal edges 22,22′ aligned. FIG. 8B shows thesubstrate sheets 18′,20′ superimposed with only one of their alignedlongitudinal edges 22,22′ being welded together at 28 a. The substratesheets 18′,20′ pass between a preferably driven rotating slit/weld anvil24 and an ultrasonic horn 26. This assembly is similar to that used inthe welding process described with respect to the closed tubular web 30in FIGS. 1-5. The ultrasonic horn 26 vibrates against the rotatingslit/weld anvil 24, welding the substrate sheets 18′,20′ together toform a continuous folded tubular web 31 open at one end. This processproduces a selvedge portion 32′ which is collected. The web is thenunfolded to form the flat web 31 shown in FIG. 8D and the weld 28 a isflattened by a flattening ultrasonic horn 33 pressing the downwardlyprojecting weld against a cylindrical driven rotating anvil 34, as shownin FIG. 8E. The cylindrical rotating anvil 34 is driven. The weldflattening process just described leaves just a slight bulge 36 in theopen multi-substrate web 31.

FIG. 9 illustrates a portion of the production line utilized inmanufacturing the open tubular web 31. The production line has twopowered supply reels 40′,42′ of the substrate sheets 18′,20′ made ofdifferent material. The substrate sheets 18′,20′ pass through anidentical roller set up (not completely shown) as previously discussedfor the closed tubular web 30 which tensions the substrate sheets18′,20′ and superimposes the opposite longitudinal edges 22,22′ of thesubstrate sheets 18′,20′.

The substrate sheets 18′,20′ are then welded together at one of theiraligned longitudinal edges 22,22′ by the vibrating ultrasonic horn 26and slit/weld anvil 24 assembly, as previously described with respect toFIG. 8B. The selvedge portion 32′ produced by the welding process isalso wound upon a driven take-up reel 64. After the substrate sheets18′,20′ are welded together, a continuous open tubular web 31 is formedhaving different appearing substrate materials. The open tubular webthen passes between drive roller 35 and nip roller 37 which pull thesubstrate sheets 18′,20′ through the welding assembly 24,26. Althoughnot shown in FIG. 9, it is understood that the open tubular web 31 canalso pass through slit sensor pins as described.

The open tubular web 31 is then unfolded prior to entering the weldflattening assembly to form an unfolded flat multi-substrate web. To aidin unfolding the open tubular web 31, the open tubular web 31 passesunder a skewed roller assembly 75 made up of skewed top driven rollers75 a,75 a which exert outward forces on the web 31 and a driven bottomroller 75 b. The unfolded multi-substrate web 31 then passes between twoidler rollers 81,33, and under a dancer tensioning roller 85, whichcontrols tension in the web 31 by adjusting the speed of the drivensupply and take-up reels 40′,47′,128. The web proceeds over a furtheridler roller 87 before entering the weld flattening apparatus. Thewelded portion 28 a of the open multi-substrate web 31 is then flattenedby the flattening ultrasonic horn 33 and cylindrical rotating anvil 34,as previously described with respect to FIGS. 8C-8E.

After the flattening process, the flat open multi-substrate web 31passes between drive and nip rollers 110,112 and over a heated camberedplate 106 to relieve the stresses produced in the welded portion 28 a ofthe is open multi-substrate web 31 from the welding process as seen inFIG. 9. The heated cambered plate 106 is identical to that described inthe embodiment for the closed tubular web 30 with respect to FIGS. 1-5.The heat subjected to the open multi-substrate web 31 relieves thestresses in the welded portion 28 a , thus minimizing ripples andproducing a flat, as well as straight open multi-substrate web 31, whichthen can be processed further with less difficulties.

The open multi-substrate web 31 continues between drive and nip rollers114,116, and under a dancer tensioning roller 119, which controlstension in the web 31. The web 31 proceeds over an idler roller 121 toan individual powered take-up reel 128 for later fabrication as shown inFIG. 9, or is immediately processed to form the cellular panel 10′.

FIG. 10 is a block diagram illustrating the steps in forming the opencellular panel 10′ of FIG. 6 formed from the flat web 31. It is verysimilar to the process for making the cellular panel 10 formed by theclosed tubular web 30 as previously discussed with respect to FIGS. 1-5.Accordingly, similar stations in FIG. 10 have been identically numberedto those in FIG. 6. One difference is the addition of folding means 55before the adhesive applying means 43. A suitable folding means isdisclosed in U.S. Pat. No. 4,450,027 or in U.S. application Ser. No.08/040,869, filed on Mar. 31, 1993, entitled “Folding Plate Assembly ForFabricating Honeycomb Insulating Material” and filed in the names ofBryan K. Ruggles and Cary L. Ruggles. As disclosed in that application,the folding means includes a slot folding plate assembly through whichthe web 31 passes. The slot is shaped to cause the outer longitudinaledges of the flat multi-substrate web 31 to raise above and over thecentral portion of the web 31, thus folding the web. The confrontinglongitudinal margins of the folded web which form the top wall portion15′ of the folded web do not contact one another, leaving a gap 57 inthe top wall portion 15′ (FIG. 6A). The folding means 55 may alsoinclude a fold setting means in the form of a heated drum (not shown)which heats the web material to its heat set temperature. The heatedfolded web is pressed against the drum to form sharp permanently setfolds. A cooling means (not shown) then cools the pressed web below thesetting temperature forming set pressed folds 13,13′ shown in FIGS. 6and 7.

The tubular web 31 next passes through adhesive applying means 43 whichapplies two bands of adhesive 11-11 ′ on the top wall portion 15′ of theopen tubular web 31 (FIG. 7). The open tubular web 31 is then cut intoidentical tubular strips by cutting means 45 which, by conveyer means,are fed to a stacking chamber 49 which may be similar to that disclosedin U.S. application Ser. No. 07/839,600, as previously discussed indetail with respect to the closed tube cellular panel 10 of FIGS. 1-5.

Embodiment of FIGS. 11-14

FIGS. 11-14 illustrate a light controlling cellular panel 10″ of thepresent invention. It comprises horizontally elongated verticallyaligned cells or tubular sections 12″ formed from an open flat tubularweb 30″. The web 30′ is folded, coated with adhesive, and cut intostrips; the strips are then stacked in the manner previously described.An opaque substrate sheet 19″ in each tubular section 12″ controls lightpassing through the panel 10″. When the opaque substrate sheet 19″ isrotated to a vertical plane, light passing through the panel isobstructed.

FIG. 11 shows a portion of the light-controlling cellular panel 10″. Thecellular panel 10″ is formed by laminating separate open tubular stripswhen in a flattened condition, as shown in FIGS. 14C and 14D, to form atubular section 12″. Each cell 12″ has a front wall portion 14″ made ofa sheer substrate sheet 18″ of one mesh size, a rear wall portion 16″made of a sheer substrate sheet 20″ of a different mesh size, a bottomwall portion 17″ made of a wider substrate sheet 19″ of opaque material,and a top wall portion 15″ which is formed by the bottom wall portion17″ of an adjacent cell 12″ and the inwardly turned upper ends of thesubstrate sheets 18″,20″ secured to the opaque sheet 19″ by spaced bandsof adhesive 11″.

The open tubular strips are first formed from a flat continuous web 30″made of three separate substrate sheets 18″,19″,20″ (FIG. 12A) which arewelded together along their longitudinal margins. FIG. 12A shows thethree superimposed substrate sheets 18″,19″,20″ with the leftlongitudinal edges 22′ and 22″ of the wider central opaque substratesheet 19″ and lower sheer substrate sheet 20″ aligned, and the rightlongitudinal edges 22″ and 22 of the central opaque substrate sheets 19″and upper sheer substrate sheet 18″ aligned. As seen in FIG. 12B, thethree-substrate sheets 18″,19″,20″ are welded together at their alignedtwo-substrate thick longitudinal edges by passing the substrate sheets18″,19″,20″ between a common vibrating ultrasonic horn 26 and slit/weldanvils 24 identical to the welding apparatus as previously described.Thus, outer sheer substrate sheet 18″ is welded to the wider opaquesubstrate sheet 19″ at the right aligned longitudinal edges thereofwhile the other outer sheer substrate sheet 20″ is simultaneously weldedto the opaque substrate sheet 19″ at the aligned left longitudinal edgesthereof to form a Z-shaped web 30″ which is unfolded, as shown in FIG.12C. When unfolded, the web 30″ has a center opaque substrate sheet 19″and outer sheer substrate sheets 18″,20″ all in the same plane.

After the welding process, the welded portions 28″ of the unfolded web30″ are flattened to form a flat web of similar thickness throughout. Asseen in FIG. 12D, the welded portions 28″ are flattened by passing theflat multi-substrate web 30″ between the flattening ultrasonic horn 33and cylindrical rotating anvil 34. The pressure applied by theflattening ultrasonic horn 33 to the welded portions 28″ of themulti-substrate web 30″ against the cylindrical rotating anvil 34flattens the welded portions 28″ to produce a multi-substrate web 30″with similar thickness throughout.

FIG. 13 shows a portion of the production line for manufacturing thecontinuous flat multi-substrate web 30″. The production line begins withdriven reels 40″,41″ and 42″ of continuous substrate sheets 18″, 19″ and20″ unwinding the sheet material therefrom. The substrate sheets18″,19″,20″ pass through similar sets of web-tensioning rollers (notshown) as discussed previously. The three-substrate sheets 18″,19″,20″are then superimposed with their longitudinal edges aligned asdescribed, by passing them in superimposed relation between a pair ofidler rollers 60″,62″ with one outer sheer substrate sheet 18″ on top,the center opaque substrate sheet 19″ in the middle, and the outer sheersubstrate 20″ on the bottom of the superimposed stack of sheets.

Each outer sheer substrate sheet 18″,20″ is then simultaneously weldedto the longitudinal edge of the center opaque substrate sheet 19″ inalignment therewith by vibrating ultrasonic horn 26 and against theslit/weld anvils 24, as previously described with respect to FIG. 12B.The selvedge portions 32″ produced by the welding process are alsorewound by take-up reels 64″. After the substrate sheets 18″,19″,20″ arewelded together, a Z-shaped web 30″ is formed. The Z-shaped web passesbetween a drive roller 35″ and a nip roller 37″ which act to pull thesubstrate sheets 18″,19″,20″ through the welding assembly. Although notshown in FIG. 13, it is understood that the web 30″ can also passthrough slit sensor pins as previously described with respect to theclosed-tube cellular panel 10.

As previously described, the Z-shaped web 30″ is then unfolded beforeentering the weld flattening apparatus to form a flat substrate sheet.To aid in the unfolding, the Z-shaped web 30″ passes beneath a skewedroller assembly 75″ comprised of driven upper rollers 75 a″,75 b″,75 c″and bottom roller 76 d. The driven rollers 75 a″ and 75 c″ overlying theouter sheet substrate sheets 18″, 20″, exert downward and outward forceson the outer sheer substrate sheets 18″ and 20″. A transverselyextending roller 75 b″ overlying the central opaque sheet 19″ exerts adownward force on the center opaque substrate sheet 19″ passing beneaththe same. The flat multi-substrate web 30″ then passes over an idlerroller 83″, under a dancer tensioning roller 85″ and over a second idlerroller 87″. The projecting welded portions 28″ of the multi-substrateweb 30″ are then flattened by the flattening ultrasonic horn 33 andcylindrical rotating anvil 34, as previously described with respect toFIG. 12D.

After the flattening process, the flattened multi-substrate web 30″passes between drive and nip rollers 110″,112″ and then over a heatedcambered plate 106 to relieve the stresses produced in the weldedportions 28″ of the multi-substrate web 30″ from the welding process.The heated cambered plate 106 is identical to that described in theembodiments of FIGS. 1-5.

The multi-substrate web 30″ then continues between further drive and niprollers 114″,116″, under a dancer tensioning roller 118″ and over anidler roller 120″ to either an individual driven take-up reel 128″ forlater fabrication as shown in FIG. 13, or immediately processed to formthe cellular panel 10″.

FIG. 14 shows a block diagram illustrating the steps of forming thelight controlling cellular panel 10″ formed from the flat unfoldedmulti-substrate web 30″. It is very similar to the process utilized tomake cellular panel 10′ formed from an open tubular web in accordancewith FIG. 10. Accordingly, corresponding reference numerals are used inFIG. 14 to avoid a repetition of description. However, the folding means55′ is different from the folding means 55 in FIG. 10 which forms sharpset folds 13′—13′ in the web 31′. The folding means 55′ includes noheated drum or other means to set any folds so that, as shown in FIG.11, there are no folds seen at the sides of the rectangular tubularsections. The folding means, therefore, preferably includes only a slotforming plate, as shown in copending application Ser. No. 839,600.

FIGS. 14A—14D illustrate respectively transverse sections of the web 30″as it unwinds from the reel 128″, and when it leaves the folding means55′ and adhesive applying means 43. Note that in FIG. 14C the bands ofadhesive 11″—11″ deposited by the adhesive applying means 43 on thefolded-over marginal portions of the outer substrate sheets 18″ and 20″overlie the outer marginal portions of the opaque substrate sheet 19″.FIG. 14D shows adjacent strips S1 and S2 cut from the web 30″ pushed inthe stacking chamber 49 where these strips are laminated together by theadhesive bands 11″—11″. Thus, when a panel 10″, shown in FIG. 11, isallowed to expand, the cells or tubular sections have the rectangularshape shown therein.

When the outer sheer substrate sheets 18″,20″, which form the front orrear wall portions 14″ or 16″ of the cellular panel 10″, are shifted upor down with respect to each other, the wide opaque substrate sheets 19″of the various laminated strips shift from a horizontal position wherelight passes through the cellular panel 10″. The opaque substrate sheets19″ are then inclined upwardly to an upstanding position where theopaque substrate sheets 19″ of adjacent strips overlap, because they arewider than the outer substrate sheets 18″, 20″. In this position, thepassage of light through the panel 10″ is prevented.

Embodiment of FIGS. 15-19

Another method of making a light controlling cellular panel comprisingof horizontally elongated vertically aligned cells utilizes an unfoldedsubstrate web 30″ identical to that formed by the production line shownin FIG. 13. However, the web 30″ is processed differently, asillustrated in FIGS. 16-19, to produce a panel 10″′ shown in FIG. 15which shows a portion of the panel 10″′. FIG. 16 shows themulti-substrate web 30″ with bands of adhesive B and B′ applied alongthe outer longitudinal margin, of the rear sheer substrate sheet 20″,and along the front margin of the opaque sheet 19″ opposite the inner orfront margin of the sheer substrate sheet 20″. The web 30″ is then cutinto strips sequentially to form three-substrate strips S1,S2,S3, etc.as shown in FIG. 17.

The closed tube cellular panel 10″′ is formed by laminating in sequencethe flat unfolded multi-substrate strips S1,S2, etc. together inidentically oriented positions at transversely spaced points therealongto the previously cut strip located above it.

As shown in FIGS. 16 and 17, the bands of adhesive B′, B of each stripthus adhere (a) the front margin 127 of the center opaque substratesheet 19″ of each strip to the outer margin 130 of the front sheersubstrate sheet 18″ of the strip above it, and (b) the outer margin 129of the rear sheer substrate sheet 20″ of the former strip to the rearmargin 131 of the center opaque substrate sheet 19″ above it. FIGS. 15Aand 15B are fragmentary views of the portion of the cellular panel 10″′of FIG. 15, showing the adhesive connections of the identicalmulti-substrate strips when the panel is expanded. When the outer margin129 of the rear sheer substrate sheet 20″ of the uppermost strip S1 andthe rear margin 127 of the center opaque substrate sheet 19″ of theuppermost strip S1 are fixed in the position they are to assume in theexpanded cellular panel 10″, and the rest of the panel 10″ is allowed todrop under the force of gravity, a light controlling panel 10″′ isformed comprising horizontally elongated vertically aligned closedtubular cells 12″′ as seen in FIG. 15. The front vertical wall 14″′ orside of each cell 12″′ is formed by the front sheer substrate sheet 18″of one of the multi-substrate strips; the rear vertical wall 16″′ orside of the cell 12″′ is formed by the rear sheer substrate sheet 20′ ofthe multi-substrate strip above it. The bottom horizontal wall 17″′ ofeach cell 12″′ is formed by the center opaque substrate sheet 19″ ofsaid one strip; and the top horizontal wall 15″′ of that cell is formedby the center opaque substrate sheet 19″′ of the strip above it. Statedanother way, the front and rear substrate sheets 18″,20″ of each stripform respectively the front and rear wall portions of adjacent cells.

In order to better understand the relationship between the various cutand laterally offset laminated multi-substrate strips S1,S2,S3,S4 shownin FIG. 17 that form the expanded panel 10′″ in FIG. 15, the frontsubstrate sheet of each strip is designated by the letter F, the centeropaque substrate sheet of each strip is designated by the letter C andthe rear substrate sheet of each strip is designated by the letter R,with the particular substrate sheet of a given strip being furtheridentified by a reference number corresponding to the reference numberidentifying that strip. Similarly, the forwardmost adhesive band of eachstrip is identified by the letter B′ and the rearmost adhesive band ofeach strip identified by the letter B, with the various adhesive bandsof the various strips each identified by a number corresponding to thenumber of the particular strip involved. Thus, the various substratesheets, adhesive bands of the various strips shown in FIG. 17 canimmediately be identified in FIG. 15.

The adjustment of the panel 10″′ to obtain the light passing andobstructing modes of operation is very similar to that of the open tubepanel 10″ of FIGS. 11-14. When the front and rear sheer substrate sheets18″,20″ of the multi-substrate strips S1,S2, etc. making up panel 10″′are shifted vertically relative to one another from their positionsshown in FIG. 15, the center opaque substrate sheets 19″ of the variousstrips of the cellular panel 10″′ are pivoted from horizontallight-passing positions to upstanding light-blocking positions. Becausethe center opaque substrate sheets 19″ are wider than the outer sheersubstrate sheets 18″,20″, the center opaque substrate sheets 19″ overlapone another in their light-blocking upstanding positions, thuspreventing any light from passing through the cellular panel 10″′.

FIG. 18 is a block diagram showing the different steps of manufacturingthe cellular panel 10″′ of FIG. 15. The laminated multi-substrate stripsforming a web 30″ are unwound from a driven supply reel 128″ and passthrough tension control and web aligning means 41′. Adhesive bands B andB′ are applied by adhesive applying means 43′ to the multi-substrate web30″ and then the web 30″ is cut by cutting means 45 into stripsS1,S2,S3, etc. The multi-substrate strips are then carried by high speedconveyor means 47, like that previously described to the raisableconveyer portion 47 b. When the first strip S1 is laminated, the liftermeans 51′ raises the raisable conveyor portion to where the first stripS1 is laminated against a leader strip (not shown) carried by anoverhead laterally indexable conveyor belt. After the first strip S1 islaminated, the second strip S2 is laminated to the first strip in thepattern described with respect to FIG. 17, and the process continueswith the third strip S3, etc. The control means 53′ control theoperating sequence of the stations of the production line justdescribed. FIG. 19 shows part of the manufacturing apparatus for makingthe light controlling closed tube cellular panel 10″′ of FIG. 15. Afterthe multi-substrate web 30″is cut into strips S1,S2,S3, etc., adhesivebands B and B′ are applied at the proper longitudinal margins aspreviously described. A conveyor belt 150, represented by the stationaryconveyor block 47 a in FIG. 18, receives the multi-substrate strips S1,S2, etc. The conveyor belt 150 is provided with suction holescommunicating with a vacuum source (not show) to hold the stripsthereon. The conveyor belt 150 conveys the strips to the raisableconveyor belt 151, represented by block 47 b in FIG. 18. The raisableconveyor belt 151 also has suction holes 156 to allow a vacuum box 154,shown in FIG. 19, to hold the multi-substrate strips in place. To beginforming the cellular panel 10″′, the first multi-substrate strip islaminated to a leader strip located on a laterally indexable conveyorbelt 160. When the first multi-substrate strip S1 is then properlypositioned, the raisable conveyor 151 delivers the strip S1 to theoverhead laterally indexable conveyor belt 160, represented by block 49′in FIG. 18.

The laterally indexable conveyor belt 160 also has suction holes 151′communicating with a vacuum box 164 to hold in place the firstmulti-substrate strip S1 adhered thereto. When the raisable conveyerbelt 151 carrying the second multi-substrate strip stops S2, striplocation sensors (not shown) in the conveyer belt structure 152 relaythe location of the second multi-substrate strip S2 to the control means53′ in FIG. 18. The control means 53′ then indexes the laterallyindexable conveyer belt 160 in the direction shown by the arrows in FIG.19 to the proper location where it stops to receive the secondmulti-substrate strip S2 delivered thereto. The raisable conveyer belt151 is part of a structure connected to hydraulically operated portions155′ of hydraulic cylinder 155 which then move the belt 151 upward tolaminate the second substrate strip S2 on raisable conveyer belt 151against the first multi-substrate strip S1 above it. This processcontinues with the subsequent strips. The belt 151 is then lowered bythe pistons 155′. The sticking force of the adhesive bands B and B′notyet fully cured, is desirably greater than the vacuum force holding thestrip on the belt. If not, vacuum pressure on the belt 151′ ismomentarily cut-off.

As this process continues, the laminated multi-substrate strips nowforming a continuous web of laminated strips pass between the laterallyindexable belt 160 and a nip roller 170. The continuous web then passesover an idler roller 172, under a dancer tensioning roller 174, whichtensions the newly formed web, and over another idler roller 176 to adriven take-up reel 178. The speed of rewind reel 178 is controlled bythe elevation of the dancer tensioning roller 174.

While the invention has been described with reference to preferredembodiments of the invention, it will be understood by those skilled inthe art that various changes and modifications may be made andequivalents may be substituted for elements thereof without departingfrom the broader aspects of the invention.

What is claimed is:
 1. An expandable and contractible cellular panelcomprising: a plurality of parallel, tubular, elongated cells securedtogether, each cell consisting of a separate first sheet and a separatesecond sheet, each sheet having a pair of longitudinal edges, eachrespective first sheet and second sheet being attached to one anotheralong at least one of their respective longitudinal edges, each cellbeing attached to an adjacent cell proximate their respectivelongitudinal edges.
 2. The cellular panel of claim 1 wherein the firstand second sheets of each cell are ultrasonically welded together alongtheir respective longitudinal edges.
 3. The panel of claim 1 wherein theadjacent cells are secured together by adhesive.
 4. The panel of claim3, wherein the longitudinal edges are not visible.
 5. The panel of claim4, wherein the proximate longitudinal edges are laterally offset fromeach other.
 6. The panel of claim 5, wherein the adhesive extends overthe longitudinal edges to join the cells together.
 7. The cellular panelof claim 1, wherein the first sheet is a woven thermoplastic materialand the second sheet is a non-woven thermoplastic material.
 8. Thecellular panel of claim 2 wherein the welded longitudinal edges have athickness substantially less than the combined thickness of the firstand second sheets.
 9. An expandable and contractible cellular panelcomprising: a plurality of parallel, aligned and elongated intermediatecells secured together, a pair of end cells, each cell consisting of afirst sheet and a second sheet, each sheet having a first and a secondlongitudinal edge, a first longitudinal margin adjacent the firstlongitudinal edge, and a second longitudinal margin adjacent the secondlongitudinal edge, each cell having: a top formed by the firstlongitudinal margins of the first and second sheets, a bottom formed bythe second longitudinal margins of the first and second sheets, a frontformed by a portion of the first sheet intermediate the first and secondlongitudinal margins thereof, and a back formed by a portion of thesecond sheet intermediate the first and second longitudinal marginsthereof, the first and second sheets being proximate to one anotheralong their respective first and second longitudinal margins, and thetop of each intermediate cell being attached to a bottom of an adjacentcell.
 10. The panel of claim 9 wherein the first and second sheets ofeach cell are ultrasonically welded together along their respectivesecond longitudinal edges.
 11. The panel of claim 10 wherein the firstand second sheets of each cell are ultrasonically welded together alongtheir respective first longitudinal edges.
 12. The panel of claim 11wherein adjacent cells are secured together by adhesive.
 13. The panelof claim 12, wherein when each cell is oriented so that the cells extendhorizontally and are in vertically-spaced relation, the secured togethermarginal portions of the sheet are located on the top or bottom wallportion of each tubular section of the panel where they are not visiblefrom the front or rear of the panel.
 14. The panel of claim 9, whereinthe longitudinal edges are not visible.
 15. The panel of claim 9,wherein the first and second sheets are ultrasonically welded togetheralong their respective first longitudinal edges.
 16. The panel of claim15, wherein the ultrasonically welded first and second pair oflongitudinal margins are laterally offset from each other.
 17. The panelof claim 12, wherein one of each of the pair of bands of adhesive arespaced apart and located on either side of the longitudinal edges. 18.The cellular panel of claim 9 wherein the first sheet is a woventhermoplastic material and the second sheet is a non-woven thermoplasticmaterial.
 19. The cellular panel of claim 16 wherein the welded portionhas a thickness substantially less than the combined thickness of thefirst and second sheets.
 20. A panel for covering windows and the like,the panel comprising: a plurality of discrete elongated open cells, eachcell comprising an upper portion, a lower portion, a front portion and aback portion, each cell made from a first sheet of a first material anda second sheet of a second material, the first and second sheets beingsecured together along at least one of their confronting longitudinalmargins, the first and second sheets of each cell being positioned inthe panel to form the front portion of the cells and the second sheetsof each cell being positioned in the panel to form the back portion ofthe cells.
 21. The panel of claim 20 wherein the first sheet and thesecond sheet are also different appearing material of the same lengthand width secured together along only one of the longitudinal marginsthereof and initially positioned in a common plane and the oppositelongitudinal marginal portions of each sheet being folded over a centralportion thereof to form an open tube, the open portion of the tubeforming each cell is closed by its securement to the central portion ofthe folded strip of the adjacent tubular section of the panel.
 22. Anexpandable and contractible cellular panel comprising: a plurality ofparallel, aligned and elongated cells secured together and aligned in asingle column, the plurality of cells including a first end cell and asecond end cell and a plurality of intermediate cells therebetween, eachcell consisting essentially of a separate first sheet and a separatesecond sheet, each sheet having a first and a second longitudinal edge,a first longitudinal margin adjacent the first longitudinal edge, and asecond longitudinal margin adjacent the second longitudinal edge, eachcell having: a top wall portion formed by the first longitudinal marginsof the first and second sheets, a bottom wall portion formed by thesecond longitudinal margins of the first and second sheets, a front wallportion formed by a portion of the first sheet intermediate the firstand second longitudinal margins thereof, and a rear wall portion formedby a portion of the second sheet intermediate the first and secondlongitudinal margins thereof, the first and second sheets being attachedto one another along at least one of their respective first and secondlongitudinal margins, and the top wall portion of each intermediate cellbeing attached to the bottom wall portion of an adjacent cell.
 23. Thepanel of claim 22 wherein the first and second sheets of each cell areultrasonically welded together along their respective secondlongitudinal edges.
 24. The panel of claim 23 wherein the first andsecond sheets of each cell are ultrasonically welded together alongtheir respective first longitudinal edges.
 25. The panel of claim 24wherein adjacent cells are secured together by adhesive.
 26. The panelof claim 25, wherein when each cell is oriented so that the cells extendhorizontally and are in vertically-spaced relation, the secured togethermarginal portions of the sheets are located on the top or bottom wallportion of each tubular section of the panel where they are not visiblefrom the front or rear of the panel.
 27. The panel of claim 22, whereinthe first and second sheets are ultrasonically welded together alongtheir respective first longitudinal edges.
 28. The panel of claim 27,wherein the ultrasonically welded first and second pair of longitudinalmargins are laterally offset from each other.
 29. The panel of claim 25,wherein the adhesive is a pair of bands of adhesive spaced apart andlocated on either side of the longitudinal edges.
 30. The cellular panelof claim 22 wherein the first sheet is a woven thermoplastic materialand the second sheet is a non-woven thermoplastic material.
 31. A panelfor covering windows, the panel comprising: a plurality of discreteelongated open cells, each cell comprising an upper portion, a lowerportion, a front portion and a back portion, each cell made from a firstsheet of a first material and a second sheet of a second material, thefirst and second sheets being secured together along at least one oftheir confronting longitudinal margins, the first and second sheets ofeach cell being positioned in the panel to form the front portion of thecells and the second sheets of each cell being positioned in the panelto form the back portion of the cells.
 32. The panel of claim 31 whereinthe first sheet and the second sheet are also different appearingmaterial of the same length and width secured together along only one ofthe longitudinal margins thereof and initially positioned in a commonplane and the opposite longitudinal marginal portions of each sheetbeing folded over a central portion thereof to form an open tube, theopen portion of the tube forming each cell is closed by its securementto the central portion of the folded strip of the adjacent tubularsection of the panel.
 33. The cellular panel of claim 1 wherein thefirst and second sheets of each intermediate cell are in contact withthe first and second sheets respectively of adjacent cells.
 34. Thecellular panel of claim 1 wherein the cells are aligned in a singlecolumn.
 35. The cellular panel of claim 1 wherein each first sheet is ofa first material and each second sheet is of a second material.
 36. Thecellular panel of claim 1 wherein the first and second sheets of eachcell are attached to one another along at least one of their respectivelongitudinal edges.
 37. An expandable and contractible cellular panelcomprising: a plurality of parallel, tubular, elongated cells securedtogether, each cell including a separate first sheet and a separatesecond sheet, each sheet having a pair of longitudinal edges, eachrespective first sheet and second sheet being attached to one anotheralong at least one of their respective longitudinal edges, wherein eachrespective first sheet is formed of a different material than eachrespective second sheet, each cell being attached to an adjacent cellproximate their respective longitudinal edges.